The present invention relates to a flow shut-off element.
In particular, the flow shut-off element according to the present invention is intended for applications in the medical field and, in greater detail, this device can be used in circuits for peritoneal dialysis.
As is known, a circuit for peritoneal dialysis consists of at least one tube connected to the patient's peritoneal cavity; in practice, the tube consists of a surgically implanted fixed catheter having an outlet inside the peritoneal cavity, and a portion outside the body to which is connected a further length of tubing designed to be replaced periodically.
The circuit thus has a first infusion line connected to one or more bags containing fresh fluid for introduction into the patient's peritoneal cavity and a second drainage line for the waste fluid, designed to carry the fluid located in the patient's peritoneal cavity to one or more bags for subsequent disposal.
In particular, the infusion and drain lines are joined by a Y-connector to a third line in communication with the fixed catheter and consequently with the peritoneal cavity.
Briefly, in a peritoneal dialysis operation the dialysis fluid which has remained for the necessary time in the patient's peritoneal cavity has to be drained off and sent to the collection bags for disposal, and the Y-connector then has to be flushed through by passing fresh fluid from the infusion line to the drain line, after which, in a final stage of infusion, a fresh fluid has to be introduced into the patient's peritoneal cavity.
Consequently, in order to carry out the aforesaid operations, it is necessary to use shut-off elements capable of operating in the area of the junction between the various tubes to ensure the correct flow of the fluids.
A first known technique requires the use of clamps (at least one for each tube), which are operated manually, thus mechanically deforming the tubing to the point at which its cross section is completely closed.
In particular, for carrying out the aforesaid operations, the infusion line is first closed to allow the fluid to pass from the patient towards the disposable bags; secondly the tubing leading towards the peritoneal cavity is closed, enabling the connection area to be washed by passing fresh fluid towards the disposable fluid bag, after which the drain line is closed, thus allowing fresh fluid to be introduced into the peritoneal cavity.
Clearly, since manual opening and closing operations have to be performed on the tubing, a degree of experience and attention is required from the user who might otherwise make mistakes in the sequence of stages, or even carry out incorrect operations which could result in serious harm to the patient's health.
A further known technique according to Patent no. EP 768099 requires the use of a stopcock consisting of a valve body on which three channels for the passage of fluids converge.
The valve body has a central cavity which communicates with the aforesaid channels, and which is designed to receive a projecting portion of a movable selector.
The rotation of the selector creates different paths for the fluid within the stopcock, these paths being created simply by the angular position of the said selector.
This stopcock is also provided with suitable projections located within the cavity formed by the valve body, and with corresponding notches formed on a cylindrical portion of the said selector.
In practice, the function of these elements is to signal to the user that the correct angular positions of the selector have been reached, these positions providing an optimal predetermined passage of fluid within the stopcock.
However, the known technique summarized above has certain drawbacks and/or operational limitations.
In the first place, the valves of the known type described above have no versatility at all, and are difficult to adapt.
If these devices were to be modified and/or adapted in any way, it would be necessary to replace most parts, if not all, of the stopcock.
Furthermore, with the aforementioned shut-off element it is not possible to specify the sequence of successive operations which the valve is to perform; in particular, the operator only has the sensation of correct positioning in the various operating conditions, but there is no indication as to the correctness of the valve opening/closing sequence being executed by the device.